This invention relates to a process for producing ultra high impact rubber-modified styrene polymers by substantially solventless mass polymerization.
There is a need for an ultra high impact styrene polymer having a 1/4 inch specimen Izod impact of at least 4 ft-lbs/inch of notch and melt flow rate (MFR) of at least 3 grams/10 minutes. Such a product would fill a gap between conventional rubber-modified polystyrene having an Izod in the range of 1 to 2 and a more expensive impact acrylonitrile-butadiene-styrene polymer. In these conventional impact resistant styrene polymers, the reinforcing agents usually employed are polybutadiene (PBD) and styrene-butadiene random copolymer (SBR) rubber. Such an ultra high impact styrene polymer product of my invention is useful especially in injection molding applications.